-- $Id: sajax.lua,v 1.6 2009/03/16 22:53:10 carregal Exp $

local cgilua = require "cgilua"
local table = require "table"
local string = require "string"
local os = require "os"
local pairs, type, tostring, xpcall = pairs, type, tostring, xpcall
local unpack = table.unpack or unpack

local xavante = require "xavante"
local httpd = require "xavante.httpd"

local _M = {}

local export_list = {}
local request_uri

if xavante and httpd then
        request_uri = function (funcname)
                return cgilua.mkabsoluteurl (cgilua.mkurlpath (cgilua.servervariable"SCRIPT_NAME" .. "/" .. funcname.. "?rs=rs"))
        end

        function _M.handle_client_request ()
                return false
        end

        local function register_path (funcname)
                return cgilua.mkurlpath (cgilua.servervariable"SCRIPT_NAME" .. "/" .. funcname)
        end

        local function handle_prefix (req, res)
                res.headers ["Expires"] = "Mon, 26 Jul 1997 05:00:00 GMT"    -- Date in the past
                res.headers ["Last-Modified"] =  os.date ("!%a, %d %b %Y %H:%M:%S GMT")
                -- always modified
                res.headers ["Cache-Control"] = "no-cache, must-revalidate"             -- HTTP/1.1
                res.headers ["Pragma"] =  "no-cache"                                                    -- HTTP/1.0

                local qry = req.parsed_url.query or ""
                local rsargs = {}
                for rs_arg in string.gfind (qry, "rsargs%[%]=([^&=]*)&?") do
                        table.insert (rsargs, rs_arg)
                end
                return rsargs
        end

        function _M.export (funcname, func)
                export_list[funcname] = func

                httpd.addHandler (nil, register_path (funcname), function (req, res)
                                local isok, result = xpcall (function ()
                                                return func (unpack (handle_prefix (req, res)))
                                        end, tostring)
                                result = result or ""
                                if isok then
                                        res.content = "+:" .. result
                                else
                                        res.content = "-:" .. result
                                end
                                return res
                        end)
        end

else

        request_uri = function (funcname)
                local uri = ""
                if string.find (uri, "?") then
                        uri = uri .. "&rs=" .. cgilua.urlcode.escape (funcname)
                else
                        uri = uri .. "?rs=" .. cgilua.urlcode.escape (funcname)
                end

                return uri
        end

        function _M.handle_client_request ()

                if not cgilua.QUERY.rs then return end

                -- Bust cache in the head
                cgilua.header ("Expires", "Mon, 26 Jul 1997 05:00:00 GMT")    -- Date in the past
                cgilua.header ("Last-Modified", os.date ("!%a, %d %b %Y %H:%M:%S GMT"))
                -- always modified
                cgilua.header ("Cache-Control", "no-cache, must-revalidate")    -- HTTP/1.1
                cgilua.header ("Pragma", "no-cache")                                                    -- HTTP/1.0

                local funcname = cgilua.QUERY.rs

                if not export_list[funcname] then
                        cgilua.put (string.format ("-:%s not callable", funcname))
                else
                        local func = export_list[funcname]
                        local rsargs = cgilua.QUERY["rsargs[]"]
                        local result

                        if not rsargs then
                                result = func()
                        elseif type (rsargs) == "string" then
                                result = func (rsargs)
                        elseif type (rsargs) == "table" then
                                result = func (unpack (rsargs))
                        else
                                return
                        end

                        cgilua.put ("+:")
                        cgilua.put (result)
                end

                return true
        end

        function _M.export (funcname, func)
                export_list[funcname] = func
        end

end


local function get_common_js ()
        return [[
                // remote scripting library
        // released under BSD license
                // (c) copyright 2005 modernmethod, inc
                var sajax_debug_mode = false;

                function sajax_debug(text) {
                        if (sajax_debug_mode)
                                alert("RSD: " + text)
                }
                function sajax_init_object() {
                        sajax_debug("rs_init_object() called..")

                        var A;
                        try {
                                A=new ActiveXObject("Msxml2.XMLHTTP");
                        } catch (e) {
                                try {
                                        A=new ActiveXObject("Microsoft.XMLHTTP");
                                } catch (oc) {
                                        A=null;
                                }
                        }
                        if(!A && typeof XMLHttpRequest != "undefined")
                                A = new XMLHttpRequest();
                        if (!A)
                                sajax_debug("Could not create connection object.");
                        return A;
                }
                function sajax_do_call(func_name, url, args) {
                        var i, x, n;
                        for (i = 0; i < args.length-1; i++)
                                url = url + "&rsargs[]=" + escape(args[i]);
                        url = url + "&rsrnd=" + new Date().getTime();
                        x = sajax_init_object();
                        x.open("GET", url, true);
                        x.onreadystatechange = function() {
                                if (x.readyState != 4)
                                        return;
                                sajax_debug("received " + x.responseText);

                                var status;
                                var data;
                                status = x.responseText.charAt(0);
                                data = x.responseText.substring(2);
                                if (status == "-")
                                        alert("Error: " + data);
                                else
                                        args[args.length-1](data);
                        }
                        x.send(null);
                        sajax_debug(func_name + " url = " + url);
                        sajax_debug(func_name + " waiting..");
                        delete x;
                }
                function sajax_call(func_name, script, callback, args) {
                        var url = script + "?rs=" + func_name;
                        args.push(callback);
                        sajax_do_call(func_name, url, args);
                }
        ]]
end

function _M.show_common_js()
        cgilua.put (get_common_js ())
end


local function get_one_stub (funcname)
        local uri = request_uri (funcname)

        return (string.format ([[
                // wrapper for %s

                function x_%s() {
                        // count args; build URL
                        sajax_do_call ("%s", "%s", x_%s.arguments);
                }
                ]], funcname, funcname, funcname, uri, funcname))
--[[
                        var i, x, n;
                        var url = "%s";
                        var a = x_%s.arguments;
                        for (i = 0; i < a.length-1; i++)
                                url = url + "&rsargs[]=" + escape(a[i]);
                        url = url + "&rsrnd=" + new Date().getTime();
                        x = rs_init_object();
                        x.open("GET", url, true);
                        x.onreadystatechange = function() {
                                if (x.readyState != 4)
                                        return;
                                rs_debug("received " + x.responseText);

                                var status;
                                var data;
                                status = x.responseText.charAt(0);
                                data = x.responseText.substring(2);
                                if (status == "-")
                                        alert("Error: " + callback_n);
                                else
                                        a[a.length-1](data);
                        }
                        x.send(null);
                        rs_debug("x_%s url = " + url);
                        rs_debug("x_%s waiting..");
                        delete x;
                }
        ] ], funcname, funcname, uri, funcname, funcname, funcname))            --]]
end

local function show_one_stub (funcname)
        cgilua.put (get_one_stub (funcname))
end

local js_has_been_shown = false

function _M.get_javascript ()
        local js = {}

        if not js_has_been_shown then
                table.insert (js, get_common_js ())
                js_has_been_shown = true
        end

        for fn,_ in pairs (export_list) do
                table.insert (js, get_one_stub (fn))
        end
        return (table.concat (js))
end

function _M.show_javascript ()
        cgilua.put (_M.get_javascript ())
end

function _M.init ()
end

return _M